Improvement in the means of operating cut-off valves



l UNITED STATES PATENT OFFICE.

WILLIAM A. FOSTER, OF FITCHBURG, MASSACHUSETTS.

IMPROVEMENT IN THE MEANS 0F OPERATING CUT-OFF-VALVES.

Specication forming part of Letters Patent No. 34,679, dated March 18, 1862.

T0 all whom it may concern,.-

Beit known that I, WILLIAM A. FOSTER, of Fitchburg, in the county of Worcester and State of Massachusetts, have invented certain Improvements in Operating the Out-Off of Steam-Engines, of which the following is a full, clear, and exact description, reference be- -ing had to the accompanying drawings, making part of this specification, in Which- Figure l is a perspective View, and Fig. 2 an elevation, of so much of an engine as is necessary to show the application of my invention.

My invention can be Inost readily applied to locomotive-engines which use a link for operating the main valve, and consists in operating the cut-off with this same link.

Heretofore the cut-oft has been operated from a sword-arm, which was vibrated by a single eccentric on one of the shafts, and a block on the end of the rod of the cut-off was moved up or down on the sword-arm to vary the cut-0E. This did not permit of such an adjustment of the single eccentric as to give the required lead to the cut-off at all parts ot the stroke of the piston, but the link being operated by two eccentrics and having, as it were, a double movement or vibration may be so adjusted by setting the two eccentrics that the required motion may be imparted from it to the cut-off.

That others skilled in the art may understand and use my invention I Will proceed to describe the manner in which I have carried it out.

In the said drawings, A is the main or driving shaft, to which are secured two eccentrics B and O. The connecting-rod D from the piston E revolves this shaft.

The link F is pivoted at a to an arm G, which is free to vibrate on the shaft b, which is secured to the frame-Work of the engine. A rod c, also pivoted to the arm G at a, and attached to the eccentric B, vibrates the arm G. Another rod d, connected with the eccentric C, is pivoted at e to the link F, and a double rocking Inotion is given to the link by the two eccentrics. l

Il is the valve-chest. The rod I which operates the main valve K is pivoted at f to a block L, which is free to slide in the curved slot g in the link F, and is held from falling out of the slot by a tongue which slides in grooves i in the link.

Another rod M, which operates the cut-off valve N, is pivoted at h to another block O, which slides in a similar manner in the slot g of the link on the side opposite to the block L. The blocks L and O are moved in the slot g from one end of the link to the other by means of hand-levers P and R, pivoted on a shaft k, the ends of each lever. being connected by a rod Z to the rods I or M.

As the motion ofthe opposite ends of the link F are different and may be varied by adj usting the two eccentrics C and B, changing the position of either of the blocks L or O in the slot g in the link F will vary the' Inovement of the valve with which the block'so changed is connected. The required move-- ment is thus ordinarily given to the main valve. I have found that by operating the cut-oft valve in the same Way I am enabled to obtain the movements which I require'to give to the cut-oft the proper amount of lead when cutting off at any portion of the stroke, which I could not obtain when the cut-olf was operated by a sword-arm vibrated by a single eccentric.

WhatI claim as my invention, and desire to secure by Letters Patent, is

Operating the cut-o valve by the link F, which operates the main valve, substantially in the manner specified.

TVM. A. FOSTER. Witnesses:

WM. F. KENNEY, JAMEs BRIERLEY. 

